Observed vs Simulated — Goodness of Fit
A physics-based simulation of this earthquake, compared against the seismograms the network actually recorded. M7.1 Ridgecrest Earthquake Sequence · 2019-07-06 03:19:53 UTC
Before reading the result
What this measurement does and does not establish.
Emulated hardware. The simulation ran on arm64 under emulation. Amplitudes are not SCEC-reference-accurate, and this measurement cannot separate the platform from the model.
One realization. A single stochastic rupture, not an ensemble. The bias below is one draw; a second run with a different seed would give a different number.
What a pass means. Consistency with recordings at these 30 stations, for this event, under this velocity model, on this hardware, within a factor of 1.99. It is not a general statement about BBP and not a prediction of accuracy at an unrecorded site.
Result
- mean |bias|
- 0.240
- a factor of 1.27×
- pass band
- 0.69
- a factor of 1.99×, declared before the run
- sigma
- 0.557
- station-to-station scatter
- cross-check
- 0.311
- recomputed here from the waveforms
The metric is ln(observed / simulated) RotD50 spectral acceleration, averaged over stations. Positive means the simulation under-predicts — real shaking was larger. Basis: BBP RotD50 residuals (authoritative).
Residual by period
Mean ln(obs/sim) at each spectral period. A structure responds at its own period, so agreement at one period says nothing about another.
| Period | Bias | Simulation | vs. band |
|---|---|---|---|
| 0.1s | -0.217 | over-predicts by 24% | within |
| 0.3s | -0.295 | over-predicts by 34% | within |
| 1s | -0.700 | over-predicts by 101% | outside band |
| 3s | -0.175 | over-predicts by 19% | within |
Goodness of fit across the spectrum
Mean residual with its ±1σ band, against the pass band. Diamonds are the Broadband Platform’s own RotD50 residuals; the line is this report’s independent recomputation from the waveforms.
Where the stations are
Each station coloured by its PGA residual. Red means the simulation under-predicted the recording; blue means it over-predicted.
Station summary — three independent sources
30 stations with both a recording and a simulated seismogram. Scroll sideways for the full set of columns.
| Station | Dist (km) |
Vs30 BBP |
Vs30 ShakeMap |
Chan | PGA (g) ShakeMap |
PGA (g) obspy |
PGA (g) BBP |
PGV (cm/s) ShakeMap |
PGV (cm/s) obspy |
PGV (cm/s) BBP |
PGD (cm) obspy |
PGD (cm) BBP |
PGD obs/sim |
ln(obs/ sim) |
Flags |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CI.TOW2 | 15.6 | 326 | 326 | HNE | 0.4287 | 0.3663 | 0.3275 | 54.1 | 52.4 | 38.2 | 25.71 | 27.79 | 0.93x | +0.112 | — |
| CI.SRT | 16.1 | 265 | 265 | HNE | 0.3112 | 0.3095 | 0.3957 | 41.9 | 42.2 | 73.6 | 20.75 | 75.74 | 0.27x | -0.246 | — |
| CI.Q0072 | 18.8 | 260 | 260 | HNE | 0.3219 | 0.2990 | 0.2741 | 32.6 | 29.3 | 40.8 | 8.07 | 28.31 | 0.28x | +0.087 | — |
| CI.WVP2 | 28.1 | 658 | 658 | HNE | 0.1831 | 0.1783 | 0.1152 | 18.3 | 16.4 | 11.8 | 8.03 | 11.68 | 0.69x | +0.437 | — |
| CI.WNM | 28.8 | 293 | 293 | HNE | 0.2249 | 0.1845 | 0.2478 | 8.6 | 7.3 | 29.8 | 4.43 | 14.18 | 0.31x | -0.295 | Outl |
| CI.WBM | 31.8 | 366 | 366 | HNE | 0.1865 | 0.2261 | 0.3085 | 15.3 | 25.1 | 39.4 | 5.67 | 26.26 | 0.22x | -0.311 | Inco,Outl |
| CI.LRL | 33.1 | 618 | 618 | HNE | 0.1950 | 0.1781 | 0.1315 | 12.7 | 12.3 | 12.0 | 4.76 | 11.91 | 0.40x | +0.304 | — |
| CI.MPM | 33.6 | 545 | 545 | HNE | 0.0905 | 0.0867 | 0.2889 | 9.9 | 12.0 | 30.0 | 7.31 | 24.53 | 0.30x | -1.204 | Inco,Outl |
| CI.CCC | 34.5 | 474 | 474 | HNE | 0.5691 | 0.4573 | 0.1168 | 74.8 | 77.5 | 11.7 | 20.34 | 7.93 | 2.57x | +1.365 | — |
| CI.WRV2 | 37.3 | 352 | 352 | HNE | 0.0996 | 0.0946 | 0.1454 | 14.9 | 13.9 | 13.7 | 5.92 | 10.53 | 0.56x | -0.429 | — |
| CI.WMF | 45.0 | 534 | 534 | HNE | 0.0594 | 0.0588 | 0.1173 | 9.1 | 7.6 | 11.8 | 5.28 | 7.87 | 0.67x | -0.691 | — |
| CI.WBS | 55.3 | 729 | 729 | HNE | 0.1646 | 0.1554 | 0.0775 | 9.5 | 9.4 | 12.8 | 2.40 | 11.68 | 0.21x | +0.696 | — |
| CI.DAW | 55.8 | 334 | 334 | HNE | 0.0576 | 0.0463 | 0.1310 | 3.0 | 3.0 | 14.7 | 1.00 | 11.53 | 0.09x | -1.040 | — |
| CI.WOR | 58.6 | 746 | 746 | HNE | 0.0923 | 0.0848 | 0.0657 | 5.3 | 4.2 | 5.7 | 1.92 | 7.89 | 0.24x | +0.256 | — |
| CI.DTP | 60.1 | 711 | 711 | HNE | 0.0342 | 0.0326 | 0.0641 | 5.6 | 6.0 | 5.3 | 3.08 | 5.62 | 0.55x | -0.676 | — |
| CE.43158 | 60.9 | 283 | 283 | HNE | 0.0582 | 0.0638 | 0.1168 | 6.3 | 11.9 | 15.5 | 7.60 | 8.13 | 0.93x | -0.605 | — |
| CI.WHF | 68.4 | 435 | 435 | HNE | 0.1036 | 0.1007 | 0.0721 | 5.4 | 5.5 | 9.5 | 1.78 | 7.02 | 0.25x | +0.333 | — |
| NN.QSM | 69.3 | 379 | 379 | HHE | 0.1144 | 0.0816 | 0.1078 | 3.4 | 3.4 | 18.4 | 3.39 | 12.97 | 0.26x | -0.279 | Glit,Outl |
| CI.CCA | 78.3 | 342 | 342 | HNE | 0.0430 | 0.0419 | 0.0639 | 4.6 | 4.4 | 10.4 | 2.81 | 10.54 | 0.27x | -0.422 | — |
| CI.ISA | 79.9 | 438 | 438 | HNE | 0.0317 | 0.0299 | 0.0581 | 2.3 | 2.2 | 5.7 | 1.25 | 6.05 | 0.21x | -0.663 | — |
| CI.Q0068 | 80.7 | 343 | 343 | HNE | 0.0021 | 0.0495 | 0.0649 | 0.6 | 4.3 | 8.8 | 2.43 | 7.66 | 0.32x | -0.270 | Outl |
| CI.APL | 81.0 | 599 | 599 | HNE | 0.0610 | 0.0599 | 0.0508 | 5.7 | 4.7 | 4.7 | 2.10 | 5.04 | 0.42x | +0.164 | — |
| CI.CWC | 86.2 | 663 | 663 | HNE | 0.0203 | 0.0165 | 0.0443 | 2.7 | 2.4 | 5.1 | 1.90 | 5.42 | 0.35x | -0.991 | — |
| CI.WAS2 | 86.5 | 784 | 784 | HNE | 0.0510 | 0.0485 | 0.0308 | 2.6 | 2.3 | 3.6 | 1.06 | 4.07 | 0.26x | +0.454 | — |
| CI.HAR | 88.6 | 344 | 344 | HNE | 0.0866 | 0.0861 | 0.0642 | 11.5 | 12.4 | 8.9 | 3.01 | 5.89 | 0.51x | +0.293 | — |
| CI.GSC | 88.7 | 371 | 371 | HNE | 0.0411 | 0.0397 | 0.0841 | 6.4 | 5.2 | 7.1 | 2.91 | 6.06 | 0.48x | -0.750 | — |
| CI.CGO | 88.7 | 713 | 713 | HNE | 0.0303 | 0.0297 | 0.0462 | 3.9 | 3.7 | 5.4 | 1.39 | 6.22 | 0.22x | -0.441 | — |
| CI.TEH | 91.4 | 780 | 780 | HNE | 0.0416 | 0.0408 | 0.0284 | 3.7 | 3.4 | 5.9 | 1.30 | 8.00 | 0.16x | +0.361 | — |
| CI.LMR2 | 93.3 | 735 | 735 | HNE | 0.0313 | 0.0279 | 0.0332 | 2.7 | 2.9 | 2.5 | 1.22 | 2.56 | 0.47x | -0.172 | — |
| NN.GWY | 95.6 | 684 | 684 | HHE | 0.0528 | 0.0346 | 0.0446 | 3.4 | 3.0 | 10.4 | 4.52 | 10.47 | 0.43x | -0.254 | Glit,Outl |
PGD is the animation pipeline's own number on both sides, read from the displacement each side hands to Blender — a different processing chain from the PGA and PGV columns, and from each other. See the displacement pages at the end.
Cross-check — how far apart are the two ‘observed’ sources?
The amplitudes the network reported in ShakeMap against the same recordings re-fetched and processed here. These should agree closely; where they do not, the ShakeMap quality flags usually explain why. A systematic offset here would be a processing fault, not physics.
Residual against distance
A trend with distance points at the attenuation model rather than the source: the simulation losing energy faster or slower than the real crust does.
Response spectra, station by station
Observed and simulated response spectra at every compared station.
Per-station detail
Nearest first. Open a station for its three-component waveform overlay and the displacement record that drives the shaking animations. Figures load when opened.
CI.TOW2 15.6 km ln(obs/sim) +0.112
CI.SRT 16.1 km ln(obs/sim) -0.246
CI.Q0072 18.8 km ln(obs/sim) +0.087
CI.WVP2 28.1 km ln(obs/sim) +0.437
CI.WNM 28.8 km ln(obs/sim) -0.295
CI.WBM 31.8 km ln(obs/sim) -0.311
CI.LRL 33.1 km ln(obs/sim) +0.304
CI.MPM 33.6 km ln(obs/sim) -1.204
CI.CCC 34.5 km ln(obs/sim) +1.365
CI.WRV2 37.3 km ln(obs/sim) -0.429
CI.WMF 45.0 km ln(obs/sim) -0.691
CI.WBS 55.3 km ln(obs/sim) +0.696
CI.DAW 55.8 km ln(obs/sim) -1.040
CI.WOR 58.6 km ln(obs/sim) +0.256
CI.DTP 60.1 km ln(obs/sim) -0.676
CE.43158 60.9 km ln(obs/sim) -0.605
CI.WHF 68.4 km ln(obs/sim) +0.333
NN.QSM 69.3 km ln(obs/sim) -0.279
CI.CCA 78.3 km ln(obs/sim) -0.422
CI.ISA 79.9 km ln(obs/sim) -0.663
CI.Q0068 80.7 km ln(obs/sim) -0.270
CI.APL 81.0 km ln(obs/sim) +0.164
CI.CWC 86.2 km ln(obs/sim) -0.991
CI.WAS2 86.5 km ln(obs/sim) +0.454
CI.HAR 88.6 km ln(obs/sim) +0.293
CI.GSC 88.7 km ln(obs/sim) -0.750
CI.CGO 88.7 km ln(obs/sim) -0.441
CI.TEH 91.4 km ln(obs/sim) +0.361
CI.LMR2 93.3 km ln(obs/sim) -0.172
NN.GWY 95.6 km ln(obs/sim) -0.254
Provenance
Simulation
- produced by
- BBP simulated
- BBP job id
- job_d80b0a978295492fac0a
- BBP version
- 22.4.0
- method
- GP
- realizations
- 1 of 1 succeeded — a single stochastic rupture, not an ensemble; the bias below is one draw
- realization used
- r0001
- sites in job spec
- —
- job submitted
- 2026-08-04T08:01:54Z
- per-site Vs30 from
- submit-time record (/app/plots/gof_work/ci38457511/compare/station_specs.json)
Source parameters
- magnitude used
- —
- hypocentre
- —
- depth
- —
- strike / dip / rake
- —
- mechanism source
- USGS moment tensor, nodal plane 1 — the conjugate plane is equally consistent with the tensor and gives different amplitudes
Velocity model
- region used
- Mojave500
- native for this location
- Mojave500 — not installed, so the run is approximate. LABasin500 carries a deep sedimentary basin that Ridgecrest does not have, which would amplify 0.3-1 s motion.
- calibration
- M7.1 against GP's ~M5.5 floor
- platform
- arm64 under emulation — amplitudes are not SCEC-reference-accurate; this number measures BBP plus Rosetta and cannot separate them
Observed data and processing
Station selection
- search radius
- 100.0 km
- policy
- all usable within radius
- stations on event
- 943
- without FDSN code
- 0 — cannot be queried at all
- candidates
- 30
- usable records
- 30 (0 returned no usable 3-component set)
- in this report
- 30 with both observed and simulated
- distance range
- 15.6 – 95.6 km
Instrumentation
- channel priority
- HN?, EN?, HH?, BH?, EH?
- channels used
- HH, HN
- data centres
- EARTHSCOPE, NCEDC, SCEDC
- mixed instrument types
- yes — strong-motion and broadband are both present, which puts a second variable into the residual
- Vs30 source
- ShakeMap stationlist (per-station)
Signal processing
- window
- origin −60.0 s to +300.0 s (requested)
- records not starting as requested
- 2 of 30 — triggered instruments whose data begins later. Each trace's true start is measured and used; assuming the requested lead would misplace them.
- response removal
- to acceleration and velocity separately, pre-filter (0.05, 0.1, 20.0, 25.0) Hz
- resampled to
- 100.0 Hz
- time origin
- t = 0 is the rupture origin for both observed and simulated traces on every overlay
How to read this report
The metric
- definition
- ln(observed / simulated) RotD50 spectral acceleration, averaged across stations at each period.
- sign
- POSITIVE means the simulation under-predicts — real shaking was larger. NEGATIVE means it over-predicts.
- scale
- It is a log ratio: ±0.10 is about ±10%, ±0.69 is a factor of 2, ±1.10 is a factor of 3.
- sigma
- The station-to-station spread around that average. A large sigma with a small bias means the model is right on average and wrong site by site.
Reading the pattern
- short-period poor,
long-period good - Points at high-frequency attenuation or near-surface site response rather than the source.
- long-period poor,
short-period good - Points at the source — corner frequency, stress drop — or at basin response in the velocity model.
- one station far off
- Usually 3D site or directivity effects that a 1D layered velocity model cannot reproduce by construction. Check whether it is driving the sigma before treating it as model error.
What this does not tell you
- A pass means the simulation is consistent with recordings at these stations, for this event, under this velocity model, on this hardware. It is not a general statement about BBP, and it is not a prediction of accuracy at an unrecorded site.